Reversible drive



May 26,1942.. l RBIRMANN.- 2,284,362y y REVERSIBLE DRIVEy Filed March so, 193e .Patented May 26, 1942 REVERSIBLE DRIVE Rudolph Birmann, Newton, Pa., assigner to Dc Laval Steam Turbine Company, Trenton, N. J., a corporation of New Jersey Appiicauon March 3o, 1938, smal No. 198,873

3 Claims.

This invention relates to a reversibledriving mechanism specifically of the type involving the use of hydraulic couplings.

The type oi hydraulic coupling disclosed in Fttinger Patent 1,199,359, dated September 26,

1916 is particularly useful for transmitting power where it is desirable to provide for some possibility of slippage and cushioning and the variable transmission of power, since it is a characteristic of this type of coupling that the lslip between the driving and driven parts depends upon the load, and may be additionally controlled by the extent to which the coupling is lled with liquid, this latter, in view of the continuous leakage depending upon the amount of liquid supplied to the coupling. In an arrangement in which a reversible drive is`to be "transmitted without gear change such hydraulic couplings may be used in pairs adapted to selectively. constantial drag between the parts rotating in opl posite directionsv preventing the drive from coming up rapidly to a full speed condition. y

It is the object of the present invention to provide a reversible drive `mechanism incorporatingv the use of a pair of hydraulic couplings, which may be of the Fttinger type or of any other suitable type, in which the idle coupling, after a lsidiary objects, particularly relating to details of execution of the invention, will become apparent from the following description read in conjunction with the accompanying drawing, in which:

Figure'l is a vertical section taken through the improved transmission unit:

Figure 2 is a vertical section taken through the liquid removing means on the plane indicated at 2--2 in Figure 1; and l Figure 3 is a transverse section taken on the plane indicated at 3-3 in Figure 2. y

The improved transmission comprises Va housing 2 provided with suitable bearings, which will be evident from the drawing, and arranged to enclose the mechanism against leakage of the drivouter ends by plugs 38.

ing and lubricating liquid. Journallcd symmetrically in the housing 2 are elements 4 and IiY constituting the driving elements of two hydraulic couplings which may be of the Fttinger type, indicated above, though it will be understood that the invention is applicable to other,` 4types of hydraulic couplings which, for their operation, depend upon the introduction of liquid.

The coupling elements 4 and 6 are provided with the impeller passages, conventionally illustrated at 8 and I0, and are provided with gear teeth, indicated at I2 and I4, throughy which they are continuously driven in opposite directions by means not shown from a prime mover. For simplicity of description, let it be assumed Vthat the gear I2`is rotating such that its upper portion is moving away from the observer, and that gear I4 is rotating in the yopposite direction, namely, with its upper end moving in the direction of the observer. Cooperating v with the impeller member 4 of the first coupling, vthere is a driven turbine or runner .member I6 provided with liquid passages conventionally illustrated at I8. This runner member is' secured to a hollow pinion 20 journalled in the housing and provided with teeth 22 designed to transmit power to the driven device. The turbine or runner member 24 associated with the secondcoupling is provided with passages 26, and, like the member I6, is secured to the pinion 20. Thus, the driven elements of the couplings are constrained to rotate in the same direction, and their` common direction will depend upon which coupling is filled with the driving liquid.

Extending through the hollow ranged to rotate and axially slide'relative thereto, is a shaft 28 which carriesat one end an annular element 30 which is provided with streamlined extensions 32 bored as indicated Aat 34 and provided withouter lateral passages 35 communicating'with' the bores 34 which are closed at their The bores 34 communicate through openings 39 with the central bore 40 of the shaft 28, which bore is closed at both its open position, through a passage 48 with the opening-A51) Yat the left hand end ofthe shaft 28,

which in turn vis in `communication with the pasf sage 52 in thecasing through which the coupling driving liquid may be introduced.

pinion 20 and ar- At the opposite end of the shaft there is provided an element 54, similar to 30, also provided with streamlined extensions 56, containing passages as described previously.` This element 54 also carries a valve flange 58 serving to control flow of driving liquid to' the second coupling through the connecting passage 60, the opening 62 and the passage 64 inthe housing.- i Y Assuming directions of rotation as indicated above, the passages 36 of the left hand element 30 open opposite the direction of rotation of the 54 and the disc 69, for the purposes hereafter mentioned.

The forward or reverse condition of the driving mechanism is determined bythe selective introduction of driving fluid into the passage 52 or 64. Assuming that the driving fluid is introduced through the passage 64, the parts will be in the condition illustrated, and the right hand coupling will be active. The liquid passes from 64 into 62, thence through the passages 60 and passages 59 into the coupling, lling the same,

while the liquid which leaks from between the coupling elements fills the space within the gear I4 and escapes through openings 10 into the surrounding housing from which it is recirculated,` with cooling, by'the liquid supply pump. At this time liquid is not supplied to the passage 52, and it will be noted that communication y between 52 and the interior of the left hand coupling is interrupted by reason of the fact that the sleeve member 44 closes the passages 46, this condition as well as the open condition of the passage 59 being achieved because of the right hand position of the shaft 28 within the hollow pinion 20. The left hand coupling will, therefore,.be vdrained throughthe passage 'I0 and cannot receive any liquid which may remain in the connections from passage 52. The result of this condition is that the pinion 22 will be driven in.l

the direction of rotation of the gear I4. The pressure of liquid at the left ofl element 54, forces it to the right against friction disc ISIv so that both elements and 54 and shaft 28 rotate as a unit with gear I4. This means that shaft 28 will have a differential movement with respect to pinion 20 due to the slip of the couplng- Y Y When it is desired to reverse the direction of rotation,v the supply of liquid through th'e passage 64 is interrupted and` driving liquid is introduced through the passage'52. The introduction of liquid under pressure into passage 52 and the removal of pressure at 64 results in theexertion of pressure at the right hand side of the element 30 through the passages 50 and 48, with theresult that the shaft 28 is moved to the left, uncovering the passages 46 and simultaneously;7 effecting the closure of the passages 58 by the sleeve 58, so that Aany residual liquid in the feeding passages for 'the rightl hand coupling is immediately cut olf from the interior of the coupling to accelerate emptying thereof. through the passages 46 into the left hand coupling. Simultaneously with this'action, 'inas` much as the right hand coupling is no longer re- Liquid now flows ceiving liquid, its liquid will escape through its leakage passage 10, entering the housing and returning to the liquid supply, vbut will also enter the space within the gear I4. The element 30 will now be rotating with the gear I2, opposite its previous direction, due to the friction disc 66, and the element 54, therefore, will also be rotating inthe opposite' direction, that is, opposite the direction of rotation of gear' I4, scooping liquid from within this gear, due to the Pitot tube action of its openings '36. and will deliver the liquid to within the gear I2. It will be noted that the relative angular velocity of the element` 54 and the liquid rotating within and with the gear I4 is double that of the gear I4 giving rise to avery considerable pressure causing flow to the left hand coupling. This pressure serves to build up a back pressure in gear I2 to fill the left hand coupling from its periphery. Thus both emptying of the right hand coupling and filling of the left hand coupling are greatly accelerated with resulting increase in the rapidity of reversal, the reversal being accomplished in a smooth fashion in View of the characteristics of the couplings, the slips of which increase asthc amount of liquid therein decreases.

The transfer of liquid from one coupling to theother. by means of the members 30 and 54 is very important, since as much as of the liquid required to ll an empty coupling is obtained by this transfer from the other coupling. The rapidity of emptying and lling is tremendously increased, and it becomes unnecessary to -provide an oil supply pump of greater capacity than is needed to keep one or the other coupling lled during unidirectional operation when the oil supply has to be merely suiiicient to take care of the spilling through holes 10, which spilling is provided in order to hold down the temperature of the oil.l If the oil pumpl would have to be made large enough to take care of completely filling and emptying the coupling member in a reasonably short time it would have to be approximately ten times the size .necessary for the present arrangement.

I'he fact thatliquid is withdrawn fromA one coupling and used to ll the other definitely pre- .vents both couplings froml being empty at the same time, thereby avoiding releaseof torque` .tion of driving liquid to the two couplings, .the

driven elements of both couplings being connect-y ed to said drivenl member wherebythe latter may be selectively driven by either, the driving elements rotating continuously to effect opxznosite,. ro' tations of the driven `member when the couplings are selectively lled with liquid, and-means for` transferring liquiddirectly from one of said couplings which is beingrendered.inoperative tothe coupling which is Ybeing rendered operativewhen a change'in direction of drive is being. effected,`

said direct transfer beingin addition tolthe 'introduction of liquid 'bysaid lselectivel liquid inv troducing means, and being effected through a.A

path additional to the paths of flow involved I ,driven elements of both couplings being connected to said driven member whereby the latter may be selectively driven by either, the driving elements rotating continuously to effect opposite rotations of the driven member when the couplings are selectively filled with liquid, and scooping means rotating, when a reversal of drive is initiated, in a direction opposite the direction of rotation of the driving element of the coupling being rendered inoperative for scooping liquid discharged from said coupling and for transferring it directly to the other coupling when a change in direction of drive is being -eiected, said direct transfer being in addition to theintroduction of' liquid by said selective liquid introducing means.

3. A reversible driving mechanism comprising a driven member, a pair of hydrauliccouplings having driving impeller elements and driven turbine elements, means for the selective introduction of driving liquid to the two couplings, the driven elements of both couplings being connected to said driven member whereby the latter may be selectively driven by either, the driving elements rotating continuously to eect opposite rotations of the driven member when the couplings are selectively lled with liquid, and means for transferring liquid directly from one of said couplings which is being rendered inoperative to the .coupling which is being rendered operative when a change in direction of drive is being effected,"

said direct transfer being in additionA to the introduction of liquid by said selective liquid intro- ,ducing means, said last named means including RUDOLPH BIRMANN.

4 cERTmcATE oF CORRECTION.l Patent my. 2,28h,362. nay 26. 19h2.

RUDOLPH BIRMANN It' is hereby certified that error appears in the above numbered patent requiring correctionas follows: In the grant, line 1, and in the heading to the printed specification, line 5, residence of.' inventor, for "Newton" read --Newtown; and that the said Letters Patent snoxildbe readwith thisv correction therein that the same me@v conform to the record of the case in 'the Patent office.

Signed and sealed this 28th day of July, A. D. 19142.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

